Screening of compounds that up-regulate Foxp3 expression. HEK 293 T cells were transfected with Foxp3 expression plasmids. ( A) Nuclear expression of Foxp3 in HEK 293 T cells was examined by immunofluorescence microscopy. Scale bar, 10 μm. ( B) Foxp3 mRNA expression in transfected HEK 293 T cells was determined by RT-PCR. ( C) Twenty-four hours after transfection, cells were then treated with different compounds for another 24 h. Foxp3 mRNA expression was analyzed by real-time RT-PCR. Data are expressed as mean ± SD, and compared with vector control (expression level of vector control was set as 1.0). Shown are results from three independent experiments.